1. Technical Field
The following description relates to one or more image forming devices such as a copy machine and printer, which are configured to selectively expose an electro-photoconductive body with an exposure unit so as to form a latent image on the electro-photoconductive body, and develop the latent image with developer so as to transfer the latent image onto a recording medium.
2. Related Art
In a conventional image forming device such as a copy machine and a printer, a laser scanning method or below-mentioned LED exposure method has been realized as an image writing method (exposure method). The LED exposure method is a method for forming a latent image on a photoconductive body by exposing a surface of the photoconductive body to light which is emitted by a light emitting unit with a plurality of light emitting elements linearly aligned and converged by a converging unit. FIG. 16 schematically shows a conventional positioning mechanism for positioning an LED head 212 with respect to a main body. There are provided three fitting portions for the positioning in total at both ends of the LED head 212.
Specifically, there are provided at an end of the LED head 212, a circular hole 221 at a lower portion, and a groove 223 at an upper portion. A lower fitting portion 200b of a pin 200 is fitted into the circular hole 221, and an upper fitting portion 200c of the pin 200 is fitted into along the groove 223. At the other end of the LED head 212, a root portion 232b of a pin 232 is fitted into an oval hole 222 formed as a through-hole.
Meanwhile, the LED head 212 is mounted on two pedestals respectively provided at front and rear sides thereof, and positioned in a height direction (y-axis direction) by adjusting the heights of the pins 200 and 232 with respect to base members 223 and 224, respectively.
In addition, the fitting portion 200b of the pin 200 and the root portion 232b of the pin 232 are fitted into the circular hole 221 and oval hole 222, respectively, and a radial fitting allowance is provided each between the circular hole 221 and fitting portion 200b and between the oval hole 222 and root portion 232b. The fitting allowance is provided for the sake of easy operations of attaching/detaching the LED head 212 and preventing a stress that may be generated in the LED head 212 by restricting spans of the main body and LED head 212 in the device as thermally-expanded (for example, see Japanese Patent Provisional Publication No. 2002-14524).